Method, apparatus and system for lining conduits

ABSTRACT

A method for inverting a tubular liner in a hollow conduit involves: forming a cuff from the tubular liner, the cuff having an opening through which the liner is fed; and while feeding the liner through the cuff opening, feeding a gas under pressure through a gas inlet port formed in the liner to a space between the cuff and the remainder of the liner, thereby causing inversion and inflation of the liner into and through the conduit. After a portion of the liner has been inverted in the conduit, a region of the cuff and liner upstream of the gas inlet port is sealed off, thereby causing inversion of the remainder of the liner in the conduit. Optionally, before a trailing end of the liner is fed through the opening of the cuff, the trailing end is sealed to prevent flow of gas therefrom. When the liner is intended to line the conduit, the liner resin-impregnated either outside or in the conduit and, after complete inversion of the liner in the conduit, the resin is cured and the ends of the liner are sealed to the inside surfaces of the conduit. An apparatus and system for conducting the method are also provided.

BACKGROUND OF THE INVENTION

This application claims priority to U.S. patent application Ser. No.11/315,328, filed on Dec. 23, 2005, which is a nonprovisionalapplication of U.S. Provisional Application No. 60/638,402, filed onDec. 27, 2004, which are hereby incorporated by reference herein.

The present invention relates to methods, apparatus or equipment andsystems for lining conduits, e.g., preferably subterranean pipelines andpassageways, such as sewers, with a liner impregnated with a curableresin in order to secure the conduit against ingress or egress ofliquids.

Subterranean passageways that have been in use for many years tend tobecome permeable, thus permitting fluids to seep into and out of thepassageways. The necessary repair of such passageways is both anexpensive and time-consuming operation. Systems of lining passagewaysthat use a fabric impregnated with curable resin have been used for anumber of years. Such systems and methods of lining passageways aredisclosed, for example, in U.S. Pat. Nos. 4,009,063; 4,064,211;4,135,958; 4,685,983; 4,668,125; 6,679,293; 5,154,936; Re. 35,944;6,390,795; 4,752,511; 5,044,405; 6,708,728; 6,354,330; 6,682,668;6,827,526; 6,641,687; and 5,969,234. Each of the foregoing referencesare incorporated by reference herein.

U.S. Pat. No. 4,009,063 to Wood discloses a method of lining apassageway, wherein a tubular fibrous felt is immersed at the passagewaysite in a thermosetting resin. The resulting resin-impregnated felt hasan inflatable tube therein which is inflated to shape the resin to thepassageway surface. As the tube is lowered into the passageway (e.g., asewer), the tube is pulled along the passageway by winding up a ropeattached to a leading end of the tube onto a hand winch. The tube can beinflated, e.g., with air under pressure from a fan or blower. With thetube so inflated, the uncured resin is either allowed to cure naturallyor is cured under the action of heat depending upon the type of resinused. The resin is cured to form a hard, rigid lining pipe with the feltembedded therein.

U.S. Pat. No. 4,064,211 to Wood discloses a method for liningpassageways, wherein a resin-impregnated foam or felt in the form of aflattened tube liner is anchored at one end of a passageway and fed intothe passageway being turned inside out as it is fed in. Before the lineris turned inside out, it is supported buoyantly by liquid, e.g., water,which serves to carry the liner. The liquid also forces the tube to rollinside out in the passageway, the uneverted portion being suspended inthe liquid. When the tube is partially filled with and floats on theliquid, the remainder of the tube may be filled with air under pressure.After the complete lining of the passageway, an outer barrier layer ofthe tube may be removed therefrom.

U.S. Pat. No. 4,135,958 to Wood discloses a method of lining apassageway with a resin absorbent tube, involving causing a tube ofresin absorbent material to evert into the passageway by applying fluidpressure to the interior of the everted tube to force the unevertedportion of the tube to move into the passageway through the evertedportion of the tube; causing a reservoir of resin to be located in theuneverted portion of the tube which is just behind the portion of thetube that is everting into the passageway, whereby the resin absorbentmaterial is soaked by the resin in the reservoir just before thatmaterial everts; and supporting the uneverted tube at the location ofthe reservoir of resin by means that move along the passageway as thetube everts, e.g., a balloon or gas-filled bag.

U.S. Pat. No. 4,685,983 to Long, Jr. discloses a method and apparatusfor installing a flexible tubular liner into a pipe, wherein theapparatus includes means for defining a pressurized region for insertingthe liner into the pipe and an insertion conduit, having an entry endand exit end connected to the means defining the pressurized region.Means are provided on the exit end of the insertion conduit for sealingand clamping the leading end of the liner to the exit end of theinsertion conduit and for creating a fluid tight seal between the linerand the insertion conduit. The liner is installed within a sewer pipe bysecuring the leading end of the liner to a fixed structure adjacent toone end or within the sewer pipe and by inverting the liner or turningthe liner inside out along the length of the sewer pipe. Once the linerreaches the halfway point in the insertion process, all of the liner islocated within the sewer pipe. The apparatus functions to insert theliner within the sewer pipe using fluid pressure, which can be acombination of water pressure and air pressure. Air pressure is made toact upon a column of water placed in the insertion conduit to pushdownwardly a cuffed leading edge of the liner, thereby causing the linerto invert and move the turned back portion of the liner toward the leftalong the sewer pipe. Pressurized fluid flows through the pressureconduit to facilitate the bending of the liner through the diversionangle. The inversion and movement of the liner along the sewer pipecontinues until the inversion end reaches and abuts against a stop meanswhich has been placed inside of the sewer pipe at the end of the sectionof pipe to be lined. Static water pressure forces the liner radiallyoutwardly against the walls of the sewer pipe. Hot water is pumpedthrough a hot water pipe into the hose which extends along the length ofthe liner. Through this circulation process, the water temperaturewithin the liner is slowly raised to a temperature sufficient to effectcuring of the liner resin.

U.S. Pat. No. 4,688,125 to Long, Jr. discloses a self-contained,transportable apparatus for inserting a flexible liner into a pipe,wherein the apparatus includes an inversion means or insertion conduit,and means for sealingly clamping a leading end of the liner with a fluidtight seal to the insertion conduit or inversion means. The apparatusfurther includes a water pipe secured to one side of the insertionconduit and adapted to be connected to a source of water, and aplurality of water valves located along the length of the water pipe tocontrol the flow of water through the water pipe. During use of theapparatus, the leading end of the liner is moved down the insertionconduit until it extends out of the exit end of the pipe. The leadingend of the liner is then turned inside out for the first six inches toform a cuff which is pulled back over the outside of the insertionconduit exit end and is secured using a clamping means. The water valvesare then opened to allow water to flow through the water pipe and toenter the top of the insertion conduit. Because the leading end of theliner is secured to the insertion conduit exit end, the water will becontained within the insertion conduit and will fill the insertionconduit. As the water pressure within the insertion conduit builds up toa predetermined level, the water pressure causes the liner to invert andmove along the pipe. The water continues to flow into the insertionconduit to maintain the water pressure at a level sufficient to move theliner along the pipe. When a trailing end of the liner reaches theinsertion conduit entry end, the operation is stopped and a rope issecured to the trailing end of the liner. When the liner has beencompletely inverted and inserted into the pipe, the liner is cured.

U.S. Pat. No. 6,679,293 to Driver discloses a process for lining anexisting pipeline with a flexible resin impregnated cured in place linerby pulling in the liner and inflating an eversion bladder with air andcuring the liner with flow-through steam without loss of pressure. Thebladder is everted by means of pressurized air. Steam is introduced intothe bladder to cure the resin, after which the bladder is removed.

U.S. Pat. No. 5,514,936 and Re. 35,944, both to Driver et al., disclosea tube eversion apparatus for use in lining passageways, e.g.,underground sewer pipes, wherein the apparatus is composed of a housinghaving an open top and an open bottom through which a tube to be evertedcan pass. The housing is composed of first and second chamberscommunicating with one another by a passage defined at least in part bya flexible wall, through which passage the tube is adapted to pass withthe flexible wall in engagement therewith. The housing further includesa third chamber with the flexible wall defining a surface thereof. Thehousing also contains a means for supplying fluid to the first chamber,means for supplying fluid at an elevated pressure to the second chamber,thereby to evert the tube out from the apparatus, and means forsupplying fluid at an elevated pressure to the third chamber, thereby topress the flexible wall against the tube as the tube moves through thepassage, so as to substantially separate the first and second chambersand to retain the elevated fluid pressure in the second chamber. Theflexible wall may extend substantially completely around the passage,thereby forming a sphincter valve which is moved to a closed,tube-engaging position by the fluid pressure in the third chamber. Thefluid used to provide the pressure to evert the tube is preferablywater. The pressure provided to the third chamber is preferably airpressure and is selected to effectively substantially seal off the upperend of the third chamber (thus separating the first and second chambers)while permitting the tube to slide therethrough.

U.S. Pat. No. 6,390,795 to Waring et al. discloses an apparatus for usein installing a liner in a conduit as part of a repair procedure,wherein the apparatus includes a sealing inlet port for passage of thetubular liner into an enclosed zone where an increased fluid pressure ismaintained to move the tubular liner into the conduit and to evert it asit moves along the conduit. The apparatus also includes a container forholding air or another fluid under pressure to act on the flexible tube.The sealing inlet port is provided in the container to allow the linerto enter the container in a flattened configuration without significantloss of pressure, so that the pressure of the fluid in the container canbe used to evert and extend the tubular liner into the required positionwithin a conduit.

U.S. Pat. No. 4,752,511 to Driver discloses a method and apparatus forsealing the space between a pipe and a lining applied to the pipe'sinterior, wherein sealing rings are provided between the lining and thepipe to prevent fluid from passing through spaces between the pipe andthe lining. The patent further teaches that water or other fluid is usedto evert the liner into and along the interior of the pipe.

U.S. Pat. No. 5,044,405 to Driver et al. discloses a method andapparatus for repairing short sections of pipe by lining them. Thepatent teaches that patch type repair is accomplished by locating thelining within a carrier which is inserted into the pipe to be repairedand moved to a position adjacent the length to be lined. The lining isthen moved out from the carrier into position with the pipe, with thecarrier providing means for pressing the lining against the interior ofthe pipe and causing it to assume final form. After the lining is formedin situ, the carrier is separated therefrom and removed from the pipe,reading for reuse. To remove the lining from the carrier, fluid pressureis applied to the liner to cause it to evert and move away from thecarrier.

U.S. Pat. No. 6,708,728 to Driver et al. discloses a “pull in andinflate” method for lining a pipeline with a flexible resin impregnatedcured in place liner. Liner is pulled into a pipeline section to berelined by pulling in the liner and inflating an eversion bladder withair and curing the liner with flow-through steam introduced in thebladder. After curing is completed, the bladder is removed.

U.S. Pat. No. 6,354,330 to Wood discloses a method of lining a pipelinewith a lining tube or resin absorbent material impregnated with acurable synthetic resin, wherein a lining tube is inserted into thepipeline and urged by pressure against the pipeline and heat is appliedin stages to lengths of the lining tube. Water is used to evert thelining tube in the pipeline.

U.S. Pat. No. 6,682,668 to Driver et al. discloses a process for liningan existing pipeline with a flexible resin impregnated cured in placeliner by pulling in the liner and inflating it with a reusable endlessinflation bladder. The bladder is everted by means of water.

U.S. Pat. No. 6,827,526 to Warren discloses an assembly for installing apipe liner within a sewer pipe, wherein the assembly includes a launcherdefining a passage through which the pipe liner and a bladder passduring installation into a branch line sewer pipe. An inflatable memberis mounted to an outer diameter of the launcher and is actuatablebetween an inflatable condition and a deflated condition. The inflatablemember defines an airtight cavity into which air is introduced by way ofan air inlet. A carrier tube is attached to the launcher body to provideprotected passage for the pipe liner and bladder tube. A seal isprovided between the launcher and the carrier tube. During installationof the pipe liner into a sewer pipe, the bladder is cuffed around theinflatable member and clamped around the outer surface of the launcher,and the pipe liner is then cuffed over the inflatable member on theoutside of the bladder. The pipe liner is impregnated with a curableresin before being installed into the launcher. The launcher is thenattached to a positioning device (e.g., a rotating/lifting machine or asystem of cables including pulleys and cables attached to the launcherand operated to pull and guide the launcher) for movement into positionwithin the sewer pipe. The positioning device and the launcher areinserted into the main line of the sewer pipe and the launcher ispositioned relative to a discrete location within the sewer pipe. Theinflatable member is then inflated to trap the bladder and the pipeliner against the inner surface of the pipe. Air pressure is thenapplied to the bladder through the carrier tube to drive the bladder andthe pipe liner into the main line sewer pipe, which causes the entirelength of the pipe liner to be drawn through the passage defined in thelauncher. The inflatable member is then deflated, but the bladderremains inflated until the pipe liner hardens. Once the pipe linerhardens, the bladder tube is deflated and the launcher removed from thesewer pipe.

U.S. Pat. No. 6,641,687 to Kiest, Jr. discloses a pipe repair apparatuswhich includes an outer carrier tube, an inner bladder tube within thecarrier tube, and a repair sleeve within the bladder tube. The bladdertube and the carrier tube are formed by one unitary tube which is foldedback upon itself. A wick extends from the repair sleeve to the rear endof the bladder tube and permits evacuation of gases from the bladdertube when the bladder tube is flattened by a vacuum during insertion ofa curable resin into the bladder tube at its forward end. The bladdertube can be inverted out of the carrier tube so as to place the repairsleeve in contact with an area to be repaired within a sewer pipe.

U.S. Pat. No. 5,969,234 to Weigele discloses an apparatus for repairingand/or leakage testing of sewer pipes, wherein the apparatus isconstructed as a tubular member surrounded by an elastic element, theapparatus further having an opening and a bladder. The bladder can beexpanded by means of an arbitrary medium, e.g., gas, air, or a liquid.Supporting wheels permit movement of the apparatus inside the sewerpipe. For repair of a damaged connecting point of a connecting pipeadjoining a sewer pipe, the opening in the apparatus is aligned with thedamaged connecting point. An interspace in the apparatus is filled witha medium, e.g., air, thereby causing the elastic element to expand andfill up the interspace. The elastic element bears against the sewer pipeinner wall and moves the apparatus up against the sewer pipe inner wall.The bladder is moved out through the opening into the connecting pipeand inflated, thereby causing the bladder to bear against the inner wallof the pipe and form a seal. Filler is then pressed into the region ofthe damaged connecting point and cured. The bladder is then reeled backinto the tubular member of the apparatus and the medium is let out ofthe interspace, thereby causing the tubular member to sink downward.

A drawback to many current pipe-lining systems is the need to halt theoperation in order to change the bladder or seal in the equipment ifripped or punctured during the installation. In addition, the existingsystems are limited to specific diameter ranges and bladders that haveto be removed after installation; therefore, more equipment, labor andtime are required to make repairs for passageways of varying diameters.

It is desirable, therefore, to provide a method and apparatus forinstalling a liner without any bladder into any diameter of subterraneanpassageways in any direction or grade that is used to carry liquids orgas, such as sewage, in which the interruption of the passageway isminimized.

The present invention is directed to improvement in production andperformance over current water-based commercial methods through use ofair over liquid. The present method and apparatus are versatile becausethey accommodate all various sizes and contours as well as variation ofthat along the length of the pipe to be lined. Furthermore, increasedproductivity can be simply achieved by replacing the apparatus (afterinstallation) with a blanking plate and moving the device to anotherlocation. The invention is also directed to rehabilitation of manholesdue to the ease in which the liner can be installed vertically. Improvedlining material is also envisioned. Re-lining of pipe systems is notimpeded relative to the slope of the pipe, that is, inversion is notimpeded by traversing the liner uphill or downhill through the pipesystem. Utilization of the liner without use of bladders and liquidreduces installation costs, specifically reducing labor and equipmentcosts. Furthermore, the apparatus utilized in the method facilitatesset-up and reduces the time during which the pipe is being serviced.Processing of the liner is improved because heating is more uniformcompared to liquid processes during the shorter processing time. Also,the time for reducing the temperature after the catalyst is activated inthe liner is significantly reduced. The apparatus is simplified overknown equipment and avoids the use of a circulation mechanism. Thepresent method avoids what is known as “soft ends”, “hold back rope”,and “bulk heads”.

SUMMARY OF THE INVENTION

The present invention is directed in part to a method for inverting atubular liner in a hollow conduit, particularly a subterraneanpassageway or pipeline, e.g., a sewer pipe, storm drain, and the like.In addition, the present invention is directed to a method for lining ahollow conduit with a resin-impregnated tubular liner, an apparatus forinverting a tubular liner in a hollow conduit, and a system for lining ahollow conduit with a resin-impregnated tubular liner. The methods aremuch simpler and faster than conventional methods for inverting a linerin a conduit and for lining a conduit. The methods, apparatus and systemof the invention require no bladder system or seal external to the lineras a material aspect of the invention. In addition, a single apparatuscan be used for all conduit diameters. The methods, apparatus and systemof this invention also minimize the time at which the conduit must beclosed during installation and curing of the liner.

Broadly, the method for inverting a tubular liner in a hollow conduitaccording to the present invention involves:

-   -   (a) forming a cuff from a leading end of a tubular liner and        securing the cuff, the cuff having an opening and being disposed        outside of the conduit;    -   (b) feeding a remainder of the liner through the opening of the        cuff;    -   (c) forming a gas inlet port in the cuff;    -   (d) while feeding the liner through the opening of the cuff,        feeding a gas (preferably air) under pressure through the gas        inlet port formed in the cuff to a space between the cuff and        the remainder of the liner that is being fed through the opening        of the cuff, thereby causing inversion and inflation of the        liner that has been fed through the opening of the cuff;    -   (e) after a portion (preferably about one-half) of the liner has        been inverted in the conduit, sealing a region of the cuff and        the liner upstream of the gas inlet port, thereby causing        inversion of the remainder of the liner fed through the opening        in the cuff; and    -   (f) optionally, before a trailing end of the liner is fed        through the opening of the cuff, sealing off the liner at a        trailing end thereof to prevent flow of gas therefrom.

The method for lining a hollow conduit with a tubular liner inaccordance with the present invention broadly involves:

-   -   (a) providing a tubular liner having a leading end;    -   (b) forming a cuff from the leading end of the liner, the cuff        having an opening and being located outside of the conduit;    -   (c) securing and positioning the cuff of the tubular liner        before a first access opening of the conduit;    -   (d) providing a gas inlet port in the cuff;    -   (e) feeding a remainder of the liner through the opening of the        cuff;    -   (f) while feeding the remainder of the liner through the opening        of the cuff, feeding gas under pressure though the gas inlet        port into a space defined between the cuff and the remainder of        the liner, the gas exerting pressure against a bottom surface of        the space between the cuff and the remainder of the liner,        thereby causing inversion and inflation of the liner into the        conduit;    -   (g) after a portion of the tubular liner has been inverted in        the conduit, restricting a region of the cuff and the liner        upstream of the gas inlet port so that gas passing through the        gas inlet port is substantially prevented from escaping to        atmosphere through the restricted region, wherein the gas        passing through the gas inlet port is forced by the sealed        region of the liner to flow through an interior portion of the        liner, thereby causing inversion and inflation of a remainder of        the liner fed through the opening in the cuff;    -   (h) optionally, before a trailing end of the liner is fed        through the opening of the cuff, closing the liner at a trailing        end thereof to prevent flow of gas thereform;    -   (i) after completion of the inversion of the liner in the        conduit, maintaining or establishing a pressure in an interior        portion of the inverted liner such that the pressure is        sufficient to keep the liner against the inside surface of the        conduit;    -   (j) curing the resin in the liner; and    -   (k) sealing leading and trailing ends of the cured liner to the        inside surface of the conduit.

In the method of this invention for lining a hollow conduit with atubular liner, the liner is impregnated with resin either before orafter the liner is inserted in the conduit.

The methods of this invention are preferably carried out in the absenceof a bladder. The gas is preferably air or steam and the pressure of thegas is preferably from about 0 to about 30 pounds per square inch (psi).Operation at atmospheric pressure requires a supplemental force toinvert the liner.

Once the liner is fully disposed within the conduit, the methods of thisinvention may further include the step of sealing off the opening of theliner cuff (e.g., with a blank plate and moving the apparatus to anotherlocation to facilitate additional installations) and then proceedingwith the remaining steps of the methods.

The conduit can be, for example, a water or gas pipe, a storm drain, asewer pipe, a wastewater drain, or the like.

The apparatus of the present invention for inverting a tubular liner ina conduit broadly contains:

-   -   a feeding member for receiving and feeding a tubular liner into        a conduit;    -   a securing element located downstream of the feeding member and        being applied to secure an opening of a cuff formed from a        leading end of the tubular liner fed through the feeding member;    -   a liner-closing member (preferably, a piston) located beneath        the securing element;    -   a gas-inlet connector located downstream of the liner-closing        member; and optionally, a control member for actuating the        liner-closing member.

The above-described apparatus is also used to line a conduit with atubular liner in accordance with the method of the invention.

The apparatus of this invention is preferably bladderless. The feedingmember is preferably composed of a single roller or a pair of rollers,the roller or rollers being rotatably mounted on a support frame.

The present invention also comprises a combination of components withthe above described apparatus. The additional components include knownapparatus to generate steam and pressurized gas, a resin impregnationunit, a monitoring unit and a refrigeration unit to facilitate the abovemethod.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic illustration of the apparatus of the inventionused in conjunction with a liner and of a first stage of the method ofthe invention.

FIG. 1B is a schematic illustration of a conduit with is to be repairedusing the apparatus shown in FIG. 1A.

FIG. 2 is an illustration of a second stage of the method of theinvention, using the apparatus shown in FIG. 1A and the conduit shown inFIG. 1B.

FIG. 3 is an illustration of the system of the invention including theapparatus shown in FIG. 1A and an illustration of a third stage of themethod of the invention.

FIG. 4 is an illustration of a fourth stage of the method of theinvention, using the apparatus and system shown in FIGS. 1A and 3 andthe conduit shown in FIG. 1B.

FIG. 5 is an illustration of a fifth stage of the method of theinvention, using the apparatus and system shown in FIGS. 1A and 3 andthe conduit shown in FIG. 1B.

FIG. 6 shows a schematic view of connector 8, using the apparatus ofthis invention.

DETAILED DESCRIPTION OF THE INVENTION

In the method of the present invention, a resin-impregnated fabrictubing liner or pre-liner (non-resin-impregnated tubing) is drawnthrough the entrance of the apparatus of this invention sufficiently toallow the first few feet of the liner to be exposed inside out from theexit point of the apparatus. The first few feet of the liner to beexposed inside out from the exit point of the apparatus is preferably atleast about 7 feet, more preferably from about 7 feet to about 15 feet,most preferably from about 10 feet to about 15 feet. The liner tube isslit on either side thereof, the length of the slit being about 2 feetor a length sufficient to allow the operator to grip and pull the linerback on itself for the first 7 feet (or other length of liner that is tobe exposed inside out from the exit point of the apparatus).

After the first few feet of the liner is exposed inside out as describedabove, a connector is attached to the liner tube. The connector is atube manufactured with an internal thread and an external thread. Afterforming a small, circular hole through the layers of the liner tube, theoperator inserts the connector tube into the hole far enough for a largeretaining washer to be placed on the tube portion extending through thehole. The retaining washer is serrated one side and smooth on the otherside. The washer is placed on the tube portion such that the serratedside of the washer is closest to the liner. The washer and the tubeportion are then secured using a large retaining nut on each side, whichare then tightened inwardly to each other, encapsulating the liner.

Generally, in the method of this invention, the connector is attached tothe liner tube to permit insertion of water or air to assist theinversion process. Lubricants can also be introduced through theconnector.

After the connector is attached to the liner tube, a length ofimpregnated fabric tubing is inserted into a conduit from a singleaccess point. The ability to control the opening or closing of theapparatus automatically or manually allows pressure to build up or bereduced and thereby assists in the speed of the inversion orinstallation of tubular fabric into the conduit. The ability to closethe entrance point of the apparatus allows internal pressure to becontrolled, which in turn forces the impregnated tubing into contactwith the walls of the conduit to form a liquid-tight seal therebetweenand to conform to the shape thereof.

With the apparatus in the restricted position, air or fluid is forcedunder pressure through the connector, causing the liner tube to expand,which in turn pulls remaining liner through itself (inversion). Anopening of the apparatus can be adjusted to reduce friction forces,which in turn can slow or accelerate the process of inverting the linertube through and into the passageway or pipeline to be repaired orlined.

Internal pressure of the liner tube against the wall of the conduit tobe lined is maintained by air or fluid flowing through the connectorinto the liner tube, thereby forcing the tube to conform to the shape ofthe existing passageway or pipeline. This same internal pressure causesthe liner tube to pull remaining liner tube through itself, therebypropelling or inverting itself further into the conduit. When the tubehas reached the halfway stage of the intended length for theinstallation, the tail or tube end is visible at the entrance point tothe apparatus. As the tail travels past the entrance point, theapparatus may then be closed and the continued application of forcethrough the connector will cause the remaining liner tube to be fullyinverted through the conduit, thereby completing the installationprocess.

Once in its final position, the resin-impregnated liner can then becured at ambient temperature or optionally by heat applied from a sourcesuch as hot air, steam or fluid supplied to the liner following throughthe connector. In a preferred embodiment of the present invention, theresin in the liner is cured by introducing air/steam or hot water intoand through the liner tube connector while maintaining sufficientpressure to overcome all or any external pressure from the ground. Theresin may be allowed to cure at an elevated ambient temperature sincethe air is introduced under pressure or the air contained between theliner may be heated by introducing hot air or steam. Additionally, hotwater can be introduced into the conduit via the connector.

The liner used in the present invention preferably has a thickness of atleast 3 millimeters. Particularly suitable thicknesses range from about3 millimeters up to about 25 millimeters. The diameter of the liner isat lest 6 inches, with particularly suitable diameters ranging fromabout 6 inches to, e.g., 146 inches.

The liner or sleeve used in the present invention can be formed of a dry(non-impregnated) fabric or resin-impregnated fabric. The fabric can beimpregnated with resin according to known methods. Reference is made,e.g., to U.S. Pat. No. 4,009,063 to Wood, which is incorporated byreference herein.

The fabric forming the lining may be formed from at least one layer ofresin absorbent material, such as felt or glass fiber or a combinationof both. The resin impregnating the fabric is preferably a syntheticthermosetting resin, of an ambient type cure, which means that it willcure with the passage of time, which may be several hours, or has othercatalyst additives which allows for the curing at a specific temperaturerange.

Liners for use in the present invention may be composed of any resinabsorbent fabric and impregnating resin conventionally used to formliners for underground conduit systems. Impregnating conduit or pipeliners with a curable resin is known in the pipe-lining art and thoseskilled in the art would recognize that many different methods ofimpregnating pipe liners are within the contemplation of this invention.Particularly suitable materials for forming conduit liners of improvedstrength are disclosed, e.g., in U.S. Pat. No. 6,837,273 and U.S.Published Application No. 200310234057, both of which are incorporatedby reference herein. These references disclose fabric layers which aresewn or bonded and which contain a natural or synthetic fibrous materialin needled, knit, woven or non-woven mat form. Suitable materials shouldbe water- and corrosion-resistant. Examples of fibers for such fabricsinclude pulp fiber, hemp, cotton, polyethylene, polypropylene, rayon,nylon, and/or polyester fibers. The references also teach that woven ornon-woven glass material can be used in addition to, or as a substitutefor, these other fibers. The references further teach that the resinousimpregnation liquid introduced into the fabric layers can be any numberof thermosetting or thermoplastic compositions which can be introducedby dipping, injecting, extruding, or painting, for example. The resinousimpregnation liquid becomes set or hardened by light or heat to providea solid matrix around the fibers. Suitable thermoplastic compositionsinclude thermoplastic polyvinyl chloride, polyolefins, and the like.Suitable thermosetting resins can include those containing aheat-activatable curing agent, a light-activatable agent, a curingagent, or a heat deactivatable curing retarding agent. Such examplesinclude ultraviolet curing unsaturated polyester, such as disclosed inU.S. Pat. No. 6,170,531 (incorporated by reference herein), e.g., vinylester, epoxy, and thermosetting polyester.

When a thermosetting resin is used to impregnate the liner, it isdesirable to maintain the resin at a reduced temperature in order toretard the curing process until the liner is fully inserted into theconduit. To maintain the resin impregnated liner at such a reducedtemperature, the liner is initially cooled at the centralized linerpreparation facility. During storage and/or transportation of the resinimpregnated liner from the liner preparation facility and the conduit tobe lined, the liner is preferably kept under refrigeration. In this way,the liner can be transported a substantial distance to a remote job sitewithout any substantial curing of the resin during transport. By using acentralized facility for the preparation of the liner, the sameequipment can be used to impregnate and otherwise prepare linersconcurrently for different jobs at widely separated job sites.

Suitable resin concentration in the impregnated liner is determined atleast in part by the natural ability of the fabric material to absorbthe various resin liquids used in the impregnation, which also dependson the viscosity and temperature at which the impregnation and the rateof impregnation can occur. These rates will change depending on thematerials, resin (e.g., resin viscosity) and fabric (e.g., fabricdensity) used.

The method and apparatus of this invention can be used to line a conduit(e.g., passageway or pipeline) of various shapes and dimensionsregardless of disposition of the conduit to be repaired or lined.Non-limiting examples of suitable conduits to be lined according to thepresent invention include those having a diameter of at least 24 inches,preferably from about 24 inches to about 54 inches, and those having alength of at least 300 feet, preferably from about 300 feet to about 900feet. However, it is to be understood that the present invention is notrestricted due to the dimensions of the conduit.

The conduit to be lined preferably extends between two access locations.A restriction valve secured through the fabric at the other end of theliner at the second access point is used to control the internalpressure of the liner or can be used to assist in the circulation of hotwater from the entrance point through the liner and returned back to theheat source. The second valve can be controlled manually orautomatically, thereby relieving or restricting the internal pressureholding the liner into shape along the entire length of the conduit.

Embodiments of the apparatus and system of this invention and thevarious stages of the methods of the present invention will now bedescribed with reference to FIGS. 1-5.

An embodiment of the apparatus within the scope of this invention isdesignated by reference numeral 4 in FIGS. 1-4. The conduit to be linede.g., a sewer pipe, is designated by reference numeral 10 and has afirst access opening in the form of a manhole 1, a second access openingin the form of a manhole 2, a first vertical channel 10A, a secondvertical channel 10B and a horizontal channel 10C disposed between thefirst and second vertical channels. It is to be understood that conduitsof various geometries and diameters can be lined using the methods,apparatus and system of this invention.

Apparatus 4 includes a conventional feeding member (not shown) forreceiving and feeding a tubular liner 3 into conduit 10, a securingelement 14 located downstream of the feeding member and being adapted tofixedly secure an opening 15A of a cuff 15 formed from leading end 3A ofliner 3; an area 16 located downstream of securing element 14; aliner-closing member 17 located in area 16, and a gas-inlet connector 8located downstream of liner-closing member 17.

In the specific embodiment shown in FIGS. 1A, 3 and 4, apparatus 4includes a supporting frame 18 having an upper platform member 19, amiddle platform member 20, a lower platform member 21, first and secondsubstantially vertical support members 5 and 22, respectively, attachedto and supporting platform members 19, 20 and 21, and a movable member 6disposed between and attached to the middle and lower platform members20 and 21. Frame 18 is preferably supported by a plurality of adjustablelegs 122 (FIGS. 2-4) for supporting the apparatus.

Member 6 is movably attached to middle platform member 20 by fittingwithin a sleeve-like socket or bearing 23 and movably attached to lowerhorizontal member 21 at sleeve-like socket or bearing 24. Using bearings23 and 24, member 6 is movable in direction in direction X (see FIG. 1A)along platform members 20 and 21, respectively. Liner-closing member 17is preferably a piston, which moves member 6 along platform members 20and 21 toward and away from member 5. Piston 17 is disposed betweenmiddle platform member 20 and lower platform member 21. Piston 17 can bemoved either manually or by means of a first control valve 7.

Middle platform member 20 is preferably disposed equidistantly fromupper and lower platform members 19 and 21, respectively, and isattached to first and second support members 5 and 22 via sleeve-likesockets or bearings 25 or 26, respectively. As pointed out above, middleplatform member 20 is also attached to member 6 via bearing 23. Lowerplatform member 21 is attached to first and second support members 5 and22 via sleeve-like sockets or bearings 27 and 28, respectively, and isalso attached to member 6 via bearing 24.

First control valve 7 is disposed on the lower platform member 21 and isadapted to actuate or cause movement of the piston along the middle andlower platform members. The control valve is preferably disposed incommunication with pressure sensors 29 and 30.

Gas-inlet connector 8 is disposed for fluid communication with agas-inlet port 31 formed in liner 3, as discussed below. Connector 8 isused to connect the gas-inlet port 31 to a gas hose 32 which blows gas,preferably air or steam, through gas-inlet port 31 into the interior ofthe liner during inversion of the liner. Gas hose 32 preferably includesa check valve 33 for opening and closing the hose. Gas hose 32 is alsopreferably connected to a lubricating member 34 for lubricating theliner.

The system of this invention includes apparatus 4 in combination with asecond or post-inversion control valve 12 for controlling flow of airthrough the liner once the liner has been fully inverted in the conduit,and a hose 11 disposed for attachment to the fully inverted liner so asto provide a substantially liquid-tight seal between the fully invertedliner and the second control valve (see FIGS. 3-5). Control valve 12 ispreferably a gate valve, and hose 11 is preferably a high temperatureand reinforced pressure hose.

FIGS. 1-5 also illustrate the use of apparatus 4 to line conduit 10,e.g., a sewer pipe. Conduit 10 is reached via manholes 1 and 2. FIG. 1Ashows liner tube 3 attached to apparatus 4 in preparation forinstallation within conduit 10. As discussed above, liner tube 3 isformed of a resin absorbent fabric or dry impregnated fabric with asynthetic thermosetting resin and has a length that is equal to orgreater than the distance between manholes 1 and 2. Liner can beinstalled in increments of about 1000 or 2000 feet depending uponconduit dimensions, logistics and physical and weight demands.

As can be seen in FIG. 1A, a leading end 3A of liner 3 is turned insideout for the first few feet to form a cuff 15 which is pulled back overupper platform member 19 and the folded edge 15B of the cuff is securedto securing element (preferably a clamp) 14 disposed on the top ofplatform member 19. The specific arrangement and design of the cuff is amatter of choice to those skilled in the art. Cuff 15 has an opening 15Athrough which liner 3 is fed. Cuff 15 is disposed above first manhole 1of conduit 10. Gas-inlet port 31 is formed in the cuff downstream ofopening 15A and downstream of piston 17.

While feeding the remainder of liner 3 through cuff opening 15A, gas,which is preferably air or steam, is introduced from gas-hose 32 throughconnector 8 and through gas-inlet port 31 into a space 35 definedbetween cuff 15 and the remainder of liner 3, space 35 being disposed inthe interior (shown in broken lines) of the cuff. The gas is fed intospace 35 under pressure (e.g., from about 0 to about 30 psig) of liner3. A 48″ diameter conduit requires gas at 3-4 psig while an 8″ diameterconduit requires gas at 20-25 psig. Increased pressures are required toinvert liner in smaller conduits. The gas introduced through port 31 isblown in so as to exert pressure against bottom 37 of liner 3, therebycausing inversion and inflation of liner 3 in conduit 10.

After a portion of the liner (preferably about one-half) has beeninverted in conduit 10, the piston 17 is actuated to bring members 5 and6 together so as to seal off a region 36 of cuff 15 and liner 3 that isdisposed upstream of gas-inlet port 31. The piston 17 may be actuatedeither manually or by using control valve 7 in an automatic mode(open/close time or pressure function). The use of control valve 7substantially restricts the escape of gas provided through connector 8.By controlling the loss of gas escaping through a sealed region 36, theprocess of inversion towards access point 1 and then through conduit 10towards access point 2 is achieved (see FIG. 1B).

Before a trailing end 3B of the liner is fed through the opening 15A ofthe cuff, the trailing end is preferably sealed off by a secondliner-sealing member (not shown) to prevent loss of gas therethrough.

In the second stage of the method of this invention, as illustrated inFIG. 2, at the halfway point of the inversion of the liner tube 3between access points 1 and 2, the piston is actuated to bring members 5and 6 together to seal off region 36, so that gas introduced viaconnector 8 is substantially prevented from escaping to atmospherethrough the sealed off area while still permitting the liner to passtherethrough. Gas supplied through connector 8 is forced by the sealingoff of region 36 to flow through the interior of the liner, therebypushing the bottom surface 37 of the liner forward. This movement inturn causes the liner to invert.

In the third stage of the method of this invention, as illustrated inFIG. 3, after the inversion has been completed in its entire length,second control valve 12 and hose 11 are positioned at access point 2.Control valve 12 is preferably a standard gate valve, and hose 11 ispreferably a high temperature and reinforced pressure hose. Hose 11 isattached to the liner tube 3 and provides a substantially fluid-tightseal between inside the liner and control valve 12. On closure ofcontrol valve 12, the flow of gas through the liner 3 now inside out orfully inverted in the conduit is restricted.

In a fourth stage of the method of this invention, illustrated in FIG.4, once the volume of the liner tube 3 or the pressure of fluid flowingthrough connector 8 has reached the optimum pressure required to keepthe liner tight against the inside walls of conduit 10, the liner willeventually cure under ambient conditions to form a new structure withinconduit 10. Optionally, a source of heat 38 can be applied throughconnector 8 relieving itself via the control valve 12, thereby speedingup the curing process.

After curing of the resin is completed, the leading and trailing ends ofthe cured liner are sealed to the inside walls of the conduit so as toprevent seepage or leakage of water or other fluid between the liner andconduit.

In an optional fifth stage of the method of this invention, illustratedin FIG. 5, once the liner tube 3 is fully in position within conduit 10and at the same time that hose 11 and control valve 12 are beingpositioned, apparatus 4 may be removed and a control blank plate 13 canbe positioned, allowing apparatus 4 to be used in another location, andstage 4 can continue as previously described

Once the liner is cured in place, it may be necessary to cut openingsfor other conduits which intersect or join with it. This can be doneusing a conventional motorized cutter that can travel the conduit linerto make appropriate openings. The device can include a camera to viewand record the cured liner. The ends or openings of the liner can besealed to the conduit using conventional sealants.

FIG. 6 shows connector 8 for injection of gas during the insertion andcuring of liner 3. It is an exploded schematic representation ofconnector 8 shown in Fig. lA after its construction and connection withair source 34. The connector shown in FIG. 6 comprises four separateparts. Element 39 is a base with a threaded portion through which gasflows. Element 40 is a disc which slips over the threaded portion ofelement 39. The threaded portion slips in the hole of element 40.Optionally, the hole can be threaded. Locking nut 41 has internalthreads which clamp liner 3 punctured to accommodate the threadedportion of element 39, liner 3 being situated between elements 39 and40, as shown in FIG. 1A. The surface of element 40 abutting liner 3 isknurled to facilitate clamping liner 3 in place. Nipple 42 is insertedin locking nut 41 and provides a means to attach a gas source toconnector 8.

The apparatus of the present invention has been described with regard toa specific embodiment. The concept present is in essence asimplification of known processes, in particular those directed to fluid(e.g., water) processes. The present design encapsulates gas to layliner in conduit. Material to the design is the gas inlet made in astationary portion of the liner itself located below the opening throughwhich liner is inverted. The apparatus is a basic design of a mechanismto hold one end of a liner while the liner is being inserted intoconduit which is to be lined. A gas is injected through a port made inthe liner after the end being held in place, and gas is charged to anannular space formed by the liner itself while it is being inverted uponitself. The end through which the invention takes place is closedsufficiently to avoid escape of gas and promote movement of liner intothe conduit. Conventional mechanisms are utilized, for example,mechanical feeding apparatus like rotating cylinder to move the liner,conventional control elements, known mechanisms to open or close the endof the liner being inverted, i.e., pistons or other closure tools, andconnector for the gas inlet. The choice of mechanism is not as importantas their sequencing and arrangement.

The system of the present invention evolves about the describedapparatus. It includes equipment to impregnate liner material and tohelp eliminate entrainment of air, if necessary. The system cam includerefrigeration equipment for impregnated liner to inhibit catalysis ofresin and assist in storage and transport of impregnated liner.Additionally, apparatus to pressurize gas or air used in the process andto make steam or heat the gaseous material.

The dimensions and design of the liner can accommodate existing conduitsfor municipal, transportation, fluid purification, drainage utilities.This can include dimensions in feet and yards perhaps limited by thestrength of the liner material relative to its weight and resistance toeffects of gas pressure need to conform the shape of the liner to theconduit being lined.

Experimental Examples 1-4

The following examples describe specific methods within the scope of thepresent invention for lining or rehabilitating a sewer pipeline. Each ofthe methods used a lining apparatus within the scope of the presentinvention. In each Example, prior to lining, the sewer pipeline wastemporarily removed from service (i.e., bypassed) by plugging thepipeline one section upstream of the work area and pumping all flowsoverland to one section downstream of the work area. The pipeline to belined was cleaned prior to installation of the liner.

Example 1

The sewer pipeline lined in Example 1 had a diameter of 33 inches and alength of 854 feet.

The liner was a polyester liner impregnated (saturated) with a polyesterthermosetting resin and having a thickness of 16 millimeters. During theimpregnation process, the entire liner was loaded into a refrigerationvehicle for transport to the site of the pipe to be lined. The combinedweight of the liner and the resin was 27,755 pounds.

Once the liner had been transported to the work area, and the equipmentset up, the first 10-15 feet of the liner was pulled from therefrigeration truck and over a top roller of the lining apparatuslocated above the manhole opening of the sewer pipeline.

The liner was situated down through open jaws or clamp of the liningapparatus. The first few feet of the liner was already turned insideout. The liner was then fixed in position, and a connector within thescope of the present invention which was previously attached to theliner was then connected to a pressure supply line. After this, the jawswere put into the closed position, and the pressure valve was opened,thereby allowing pressure to build up inside the exposed liner andcausing the liner to expand into a round pipe shape. The jaws wereadjusted fractionally and the pressure maintained at 2-5 pounds persquare inch (psi). The liner begins to invert. Simultaneously, remainingliner in the truck is pulled down from the truck and over the top rollerof the lining apparatus.

Inversion of the liner continued until the liner inverted down into themanhole opening in a vertical position and reached the floor of themanhole. When the inverted liner reached the manhole floor, the pressurevalve was switched off, and the jaws were opened to allow trapped air toescape to atmosphere. This allowed an operator of the apparatus toverify that the liner had reached the manhole floor.

An operator was lowered into the manhole to attach a turn rope to theliner material. A “turn rope” is a knotted rope threaded into one ormore outside layers of the liner. It should be noted here that if theconventional method of using water as the means for exerting pressure,the water would have to be removed first before the operator could enterthe manhole. The turn rope was then pulled vertically, this movementcausing the liner to be repositioned from a vertical position to ahorizontal position, thereby allowing the inversion of the liner tocontinue horizontally through the pipeline. Repositioning the liner froma vertical position to a horizontal position generally takes about 8 to10 minutes.

After repositioning the liner, the operator leaves the manhole. Theclamp is then closed and the pressure turned on, thereby permitting theprocess to continue. After approximately 8 to 10 minutes, the halfwaystage of the process is reached. At this stage, all or nearly all of theliner has passed into the sewer pipeline, and the liner has beeninverted approximately half the way through the length of the pipeline.After the end of the liner has passed through the jaws, the jaws arefully closed.

By monitoring a pressure gauge, the operator can easily identify theinversion process because an increase in pressure means the liner hasstopped inverting.

Once the liner inverts (i.e., turns inside out) and the outside layersof the liner are stretched to the pipeline wall, the combinedrestriction of the jaws at the entry point of the apparatus and theinternal pipeline wall will cause the liner to stretch at the inversionface, which in turn causes the liner to invert through itself.

Within three minutes of fully closing the jaws, the liner reached itsdestination at the other end of the pipeline. An operator then connecteda control valve station and temperature thermal wires to a temperaturemonitor. Via radio communication between an operator at the inversionentry point and an operator at the control valve station, pressure andtemperature readings are adjusted and recorded for the entire liner,which is now completely in place.

Once the operators had established the correct air pressure, steam wasthen introduced into a supply line, which increased the internaltemperature of the liner to a point that would cause an exothermicreaction to occur, which in turn ensures that the soft, flexible,saturated resin layer becomes a hard fixed pipe within the pipe.

Once the liner is cured in place, the steam is switched off and theinternal liner cooled to a temperature of about 120° F. Excess liner atboth ends was cut off.

Example 2

The sewer pipeline lined in Example 2 had a diameter of 54 inches and alength of 421 feet.

The liner was a polyester liner impregnated (saturated) with a polyesterthermosetting resin and having a thickness of 25 millimeters. During theimpregnation process, the entire liner was loaded into a refrigerationvehicle for transport to the site of the pipe to be lined. The combinedweight of the liner and the resin was 34,853 pounds. A turn rope wasattached to the liner after the impregnation process was completed andbefore the final 15 feet of the liner had been loaded into therefrigeration truck.

Once the liner had been transported to the work area, and the equipmentset up, the first 10-15 feet of the liner was pulled from therefrigeration truck and over a top roller of the lining apparatus. Theapparatus was located above the shaft entrance of the sewer pipeline.

The liner was situated down through open jaws or clamp of the liningapparatus. The first seven feet of the liner was already turned insideout. The liner was then fixed in position, and a connector within thescope of the present invention which was previously attached to theliner was then connected to a pressure supply line. After this, the jawswere put into the closed position, and the pressure valve was opened,thereby allowing pressure to build up inside the exposed liner andcausing the liner to expand into a round pipe shape. The jaws wereadjusted fractionally and the pressure maintained at 2-5 psi. The linerbegins to invert. Simultaneously, remaining liner in the truck is pulleddown from the truck and over the top roller of the lining apparatus.

Inversion of the liner continued until the liner inverted down into themanhole opening in a vertical position and reached the floor of themanhole. When the inverted liner reached the manhole floor, the pressurevalve was switched off, and the jaws were opened to allow trapped air toescape to atmosphere. This allowed an operator of the apparatus toverify that the liner had reached the manhole floor.

The turn rope was then pulled vertically, this movement causing theliner to be repositioned from a vertical position to a horizontalposition. The jaws were then closed and the pressure turned on, therebypermitting the process to continue. After approximately 12 minutes, thehalfway stage of the process is reached. At this stage, all or nearlyall of the liner has passed into the sewer pipeline, and the liner hasbeen inverted approximately half the way through the length of thepipeline. After the end of the liner has passed through the jaws, thejaws are fully closed.

As noted above, by monitoring a pressure gauge, the operator can easilyidentify the inversion process because an increase in pressure means theliner has stopped inverting.

Once the liner inverts (i.e., turns inside out) and the outside layersof the liner are stretched to the pipeline wall, the combinedrestriction of the jaws at the entry point of the apparatus and theinternal pipeline wall will cause the liner to stretch at the inversionface, which in turn causes the liner to invert through itself.

Within five minutes of fully closing the jaws, the liner reached itsdestination at the other end of the pipeline. An operator confirmed thisusing radio communication. The air supply was then turned off. Due toother construction activities in the area, the operators then removedthe lining apparatus from its location and connected a control valvestation to the connector that was still attached to the liner and a setof clamps to the end of the liner. Similarly, at the destinationmanhole, an operator carried out the same operation. Once completed andvia radio communication, air was reintroduced from the other end(destination manhole).

Once the operators had established the correct air pressure, steam wasthen introduced into a supply line at the destination end and ventedthrough the connector and valve control station at the inversion end,which increased the internal temperature of the liner to a point thatcaused an exothermic reaction to occur, which in turn ensured that theonce soft and flexible, saturated resin layers to become a hard fixedpipe within a pipe.

Once the liner is cured in place, the steam is switched off and theinternal liner cooled to a temperature of approximately 120° F. Excessliner at both ends was cut off and removed.

Example 3

The sewer pipeline lined in Example 3 had a diameter of 36 inches and alength of 300 feet.

The liner was a polyester liner impregnated (saturated) with a polyesterthermosetting resin and having a thickness of 22.5 millimeters. Duringthe impregnation process, the entire liner was loaded into arefrigeration vehicle for transport to the side of the pipe to be lined.The combined weight of the liner and the resin was 14,907 pounds.

Once the liner had been transported to the work area, and the equipmentset up, the first 10-15 feet of the liner was pulled from therefrigeration truck and over a top roller of the lining apparatus. Theapparatus was situated at the rear end of a specially modified boilertruck having a hydraulic mast capable of moving up and down similar to aforklift. The boiler truck was positioned immediately above the manholeopening of the downstream manhole to the sewer pipeline. Thus, inExample 3, the installation process was reversed and the liner wasinverted uphill.

The liner was situated down through open jaws or clamp of the liningapparatus. The first seven feet of the liner was already turned insideout. The liner was then fixed in position, and a connector within thescope of the present invention which was previously attached to theliner was then connected to a pressure supply line. After this, the jawswere put into the closed position, and the pressure valve was opened,thereby allowing pressure to build up inside the exposed liner andcausing the liner to expand into a round pipe shape. The jaws wereadjusted fractionally and the pressure maintained at 5-8 psi. The linerbegins to invert. Simultaneously, remaining liner in the truck is pulleddown from the truck and over the top roller of the lining apparatus.

Inversion of the liner continued until the liner inverted down into themanhole opening in a vertical position and reached the floor of themanhole. When the inverted liner reached the manhole floor, the pressurevalve was switched off, and the jaws were opened to allow trapped air toescape to atmosphere. This allowed an operator of the apparatus toverify that the liner had reached the manhole floor.

The first 10-15 feet of the liner was dry tube (i.e., no resinsaturation). Once it was established that the liner had reached themanhole floor, the hydraulic mast was moved upward, leaving a gapbetween the inversion face of the liner and the manhole floor. Theprocess of inversion was allowed to continue until sufficient materialhad entered into the manhole to make the turn from the vertical positioninto the horizontal position in order to enter the pipeline. Airpressure was then turned off, and the jaws opened to allow the trappedair to escape to atmosphere. Having established that there was bothsufficient material now turned inside out into the manhole and that theresin could be seen from the exposure of the saturated liner, theoperator of the apparatus then lowered the hydraulic mast approximately3-4 feet, allowing the liner's first few feet to be in the horizontalposition, with the remainder of the liner hanging vertically. This mastmovement caused the liner to rest upon the manhole floor, and directedthe inversion face toward the pipeline entranceway (turning through 90degrees). The jaws were then closed and the pressure turned on, therebypermitting the process to continue. After approximately 6 minutes, thehalfway stage of the process is reached. At this stage, all or nearlyall of the liner has passed into the sewer pipeline. After the end ofthe liner has passed through the jaws, the jaws are fully closed.

As pointed out before, by monitoring a pressure gauge, the operator caneasily identify the inversion process because an increase in pressuremeans the liner has stopped inverting. A sudden decrease in pressurewould indicate the liner had reached its destination if the liner wasnot sealed off at the end.

Once the liner inverts (i.e., turns inside out) and the outside layersof the liner are stretched to the pipeline wall, the combinedrestriction of the jaws at the entry point of the apparatus and theinternal pipeline wall will cause the liner to stretch at the inversionface, which in turn causes the liner to invert through itself.

Within two minutes of fully closing the jaws, the liner reached itsdestination at the upstream end of the pipeline. An operator confirmedthis using radio communication. The air supply was then turned off. Anoperator then connected a control valve station and temperature thermalwires to a temperature monitor. Via radio communication between anoperator at the inversion entry point and an operator at the controlvalve station, pressure and temperature readings are adjusted andrecorded for the entire liner, which is now completely in place.

Once the operators had established the correct air pressure, steam wasthen introduced into a supply line at the inversion end and vented toatmosphere at the upstream end, through the connector and valve controlstation, which increased the internal temperature of the liner to apoint that caused an exothermic reaction to occur, which in turn ensuredthat the once soft and flexible, saturated resin layers to become a hardfixed pipe within the pipe.

Once the liner is cured in place, the steam is switched off and theinternal liner cooled to a temperature of approximately 120° F. Excessliner at both ends was cut off and removed.

Example 4

The sewer pipeline lined in Example 4 had a diameter of 24 inches and alength of 300 feet.

The liner was a polyester liner impregnated (saturated) with a polyesterthermosetting resin and having a thickness of 15 millimeters. Theclosest access point to the manhole entrance was about 125 feet awayfrom the lining apparatus. Thus, the liner was approximately 425 feet inlength, with only about 300 feet being saturated with resin.

During the impregnation process, the entire liner was loaded into arefrigeration vehicle for transport to the site of the pipe to be lined.The combined weight of the liner and the resin was 6640 pounds.

Once the liner had been transported to the work area, and the equipmentset up, the first 10-15 feet of the liner was pulled from therefrigeration truck and over a top roller of the lining apparatus. Theapparatus was situated at the rear end of a specially modified boilertruck having a hydraulic mast capable of moving up and down similar to aforklift. The boiler truck was positioned approximately 120 feet awayfrom the manhole opening to the sewer pipeline. The reason for thetruck's distance from the manhole opening was the presence of a drycreek riverbed located 20 feet below the top of the manhole and runningparallel to the pipeline. Access to the other side of the manhole wasimpossible because of the presence of a large railway track also runningparallel to the pipeline.

The liner was situated down through open jaws or clamp of the liningapparatus. The first seven feet of the liner was already turned insideout. After this, the jaws were put into the closed position, and thepressure valve was opened, thereby allowing pressure to build up insidethe exposed liner and causing the liner to expand into a round pipeshape. The jaws were adjusted fractionally and the pressure maintainedat 8-10 psi. The liner begins to invert. Simultaneously, remaining linerin the truck is pulled down from the truck and over the top roller ofthe lining apparatus.

Inversion of the liner continued until the liner inverted along a trailabove ground and then down into the creek riverbed and up a steepincline to the manhole entrance. The liner was inverted past the manholeentrance for several feet until it was established that there wassufficient material above ground to be capable of reaching the manholefloor once the liner was repositioned. An operator also established thatthere was sufficient wet resin being exposed inside out so that whenresituated, the dry liner would not be inside the pipe. The pressurevalve was switched off, and the jaws were opened to allow trapped air toescape to atmosphere. This allowed operators of the apparatus tomanually lift the liner and lower it into the manhole so that theexposed inversion face of the liner was placed into the pipelineentrance for several inches. The jaws were then closed and the pressureturned on, thereby permitting the process to continue. Afterapproximately 20 minutes, the halfway stage of the process is reached.At this stage, all or nearly all of the liner has passed into the sewerpipeline, and the liner has been inverted approximately one-third of theway through the length of the pipeline. After the end of the liner(which in this application was sealed around a connector) had passedthrough the jaws, the jaws are fully closed.

By monitoring a pressure gauge, the operator could identify theinversion process because an increase in pressure indicates that theliner has stopped inverting. In this application, an operator alsomonitored the downstream location manhole and signaled, via radiocommunication, that the liner had reached its destination, and the linersealed off and in the correct position at the end.

Once the liner inverts (i.e., turns inside out) and the outside layersof the liner are stretched to the pipeline wall, the combinedrestriction of the jaws at the entry point of the apparatus and theinternal pipeline wall will cause the liner to stretch at the inversionface, which in turn causes the liner to invert through itself.

Within ten minutes of fully closing the jaws, the liner reached itsdestination point at the end of the pipeline. An operator confirmed thisusing radio communication. The air supply was then reduced in pressureto allow the operator to safely connect a control valve station andtemperature thermal wires to a temperature monitor. Via radiocommunication between an operator at the inversion entry point and anoperator at the control valve station, pressure and temperature readingsare adjusted and recorded for the entire liner, which is now completelyin place.

Once the operators had established the correct air pressure, steam wasthen introduced into a supply line at the inversion end and vented toatmosphere at the upstream end, through the connector and valve controlstation, which increased the internal temperature of the liner to apoint that caused an exothermic reaction to occur, which in turn ensuredthat the once soft and flexible, saturated resin layers to become a hardfixed pipe within the pipe.

Once the liner is cured in place, the steam is switched off and theinternal liner cooled to a temperature of approximately 120° F. Excessliner at both ends was cut off and removed.

The apparatus and method of this invention can be used for theinstallation of any cured-in-place product or pre-liner or dry linertube (non-resin-saturated liner) into any conduit (e.g., manhole,pipeline, or vertical shaft) used to convey fluids or gas. In the methodof the present invention, the length of time required for curing theliner will depend on a variety of factors, such as, e.g., soiltemperature, the material constituting the liner, the material making upthe particular conduit being lined (e.g., brick, concrete, clay,plastic, iron, et al.), the heat conductivity of the material making upthe conduit being lined, the particular groundwater conditions, the dipsand sags present within the conduit being lined, the thickness of theliner, the size and capacity of the air supply, the size and capacity ofthe power source of steam units used, the size of air dryer or steamtrap, as well as the size of pipe supply and control valve, and flowdirection. The particular resin used to impregnate the liner alsoaffects curing times. For example, thermosetting polyester, vinyl esterand epoxy resins will be used in different amounts and will usedifferent catalysts (thermosetting resins are all mass critical).

The foregoing description of the invention is thus illustrative andexplanatory, and various changes in the equipment, as well as in thedetails of the methods and techniques disclosed herein may be madewithout departing from the spirit of the invention, which is defined bythe claims.

1. A method for inverting a tubular liner in a hollow conduit,comprising: (a) forming a cuff from a leading end of a tubular liner andsecuring the cuff, the cuff having an opening and being disposed outsideof the conduit; (b) feeding a remainder of the liner through the openingof the cuff; (c) forming a gas inlet port in the cuff; (d) while feedingthe liner through the opening of the cuff, feeding a gas under pressurethrough the gas inlet port formed in the cuff to a space between thecuff and the remainder of the liner that is being fed through theopening of the cuff, thereby causing inversion and inflation of theliner that has been fed through the opening of the cuff; (e) after aportion of the liner has been inverted in the conduit, sealing a regionof the cuff and the liner upstream of the gas inlet port, therebycausing inversion of the remainder of the liner fed through the openingof the cuff; and (f) optionally, before a trailing end of the liner isfed through the opening of the cuff, sealing off the liner at a trailingend thereof to prevent flow of gas therefrom.
 2. A method according toclaim 1, wherein the method is carried out in the absence of a bladder.3. A method according to claim 1, wherein the gas is air.
 4. A methodaccording to claim 1, wherein the gas is steam.
 5. A method according toclaim 1, wherein the pressure at which the gas is fed is from about 0 toabout 30 psi.
 6. A method according to claim 1, wherein step (e) iscarried out after about one-half of the liner has been inverted in theconduit.
 7. A method according to claim 1, wherein the conduit is awater or gas pipe, a storm drain, a sewer pipe, or a wastewater drain.8. A method for lining a hollow conduit with a tubular liner,comprising: (a) providing a tubular liner having a leading end; (b)forming a cuff from the leading end of the liner, the cuff having anopening and being located outside of the conduit; (c) securing andpositioning the cuff of the liner before a first access opening of theconduit; (d) providing a gas inlet port in the cuff; (e) feeding aremainder of the liner through the opening of the cuff; (f) whilefeeding the remainder of the liner through the opening of the cuff,feeding gas under pressure through the gas inlet port formed in the cuffto a space between the cuff and the remainder of the liner, therebycausing inversion and inflation of the liner into and through theconduit; (g) after a portion of the tubular liner has been inverted inthe conduit, restricting region of the cuff and the liner upstream ofthe gas inlet port so that gas passing through the gas inlet port issubstantially prevented from escaping to atmosphere through the sealedregion, wherein the gas passing through the gas inlet port is forced bythe restricted region of the liner to flow through an interior portionof the liner, thereby causing inversion and inflation of a remainder ofthe liner fed through the opening in the cuff; (h) optionally, before atrailing end of the liner is fed through the opening of the cuff,restricting the trailing end to prevent flow of gas therefrom; (i) aftercompletion of the inversion of the liner in the conduit, maintaining orestablishing a pressure in an interior portion of the inverted linersuch that the pressure is sufficient to keep the liner against theinside surface of the conduit; (j) curing the resin in the liner; and(k) sealing leading and trailing ends of the cured liner to the insidesurface of the conduit.
 9. A method according to claim 8, wherein thetubular liner has been impregnated with a resin prior to inversion inthe conduit.
 10. A method according to claim 8, wherein the tubularliner is impregnated with a resin in the conduit.
 11. A method accordingto claim 8, wherein the method is carried out in the absence of abladder.
 12. A method according to claim 8, wherein the gas is air. 13.A method according to claim 8, wherein the gas is steam.
 14. A methodaccording to claim 8, wherein step (g) is carried out after aboutone-half of the liner has been inverted in the conduit.
 15. A methodaccording to claim 8, wherein the conduit is a water or gas pipe, astorm drain, a sewer pipe, or a wastewater drain.
 16. A method accordingto claim 8, further comprising, once the liner is fully disposed withinthe conduit, sealing off the opening of the cuff of the liner, andproceeding with remaining steps of the method.
 17. An apparatus forinverting a tubular liner in a conduit, comprising: a feeding member forreceiving and feeding a tubular liner into a conduit; a securing elementlocated downstream of the feeding member and constructed to secure anopening formed from a leading end of a tubular liner fed through thefeeding member; a liner closing member located downstream of thesecuring element; and a seal adjacent to the securing element comprisingthe outer surface of the tubular liner passing against itself.
 18. Anapparatus according to claim 17, further comprising a first controlmember for actuating the liner-closing member.
 19. An apparatusaccording to claim 17, wherein the apparatus is bladderless.
 20. Anapparatus according to claim 17, wherein the liner-closing member is apiston.
 21. An apparatus according to claim 17, wherein said feedingmember includes a single roller or pair of rollers, the roller or pairof rollers being mounted rotatably on a support frame.
 22. A system foruse in lining a hollow conduit with a liner, comprising: (A) anapparatus external to the conduit, comprising: a feeding member forreceiving and feeding a tubular liner into a conduit; a securing elementlocated downstream of the feeding member and constructed to secure anopening formed from a leading end of a tubular liner fed through thefeeding member; a liner closing member located downstream of thesecuring element; a seal adjacent to the securing element comprising theouter surface of the tubular liner pressed against itself; a gas-inletlocated downstream of the liner closing member optionally, a firstcontrol member for actuating the liner closing member to seal off aregion of a tubular liner passing adjacent to the liner sealing member;and (B) a second control member for controlling flow of gas through theliner once the liner has been fully inverted in the conduit.
 23. Asystem according to claim 22, wherein the system is bladderless.
 24. Asystem according to claim 22, wherein the second member is a gate valve.25. A system according to claim 22, wherein the liner closing member isa piston.
 26. A method for lining conduits with inverted curable liningmaterial comprising encapsulating pressurized gas by forming a sealcomprising the outer surface of a tubular lining material pressedagainst itself.
 27. An apparatus for lining conduit with invertedcurable lining material comprising a mechanism to invert said linerhaving a member to press the outer surface of the liner against itselfto form a seal, and optionally a gas inlet formed in the liner materialsecured to said mechanism whereby pressurized gas effects movement ofliner material through said conduit.
 28. An apparatus according to claim17, further comprising a gas-inlet located downstream of the linerclosing member.
 29. A feeder for use in installing a flexible tubularliner into a pipe, comprising: (a) a generally tubular body of flexiblematerial having: (i) a mouth end defining an open mouth; (ii) an outfeedend opposite said mouth end; (iii) a throat portion defined between saidmouth and said outfeed end; and (iv) a pressure-containing section ofsaid tubular body extending from said throat portion to said outfeedend, said outfeed end being attachable to a near end of a tubular linerso as to provide a fluid-tight communication between an interior of saidpressure-containing section and an interior of said tubular liner; and(b) a fluid inlet port defined in said pressure-containing section andcommunicating with said interior of said pressure-containing section.30. A liner installation apparatus for use in installation of a flexibletubular liner in a pipe, the apparatus comprising: (a) a length offlexible tubular liner of a size intended to fit within said pipe as aninstalled liner; (b) a feeder including a generally tubular body offlexible material, having: (i) a mouth end defining an open mouth; (ii)an outfeed end opposite said mouth end; (iii) a throat portion definedbetween said mouth and said outfeed end; and (iv) a pressure-containingsection of said tubular body, extending from said throat portion to saidoutfeed end, said outfeed end being attachable to a near end of atubular liner so as to provide a fluid-tight communication between aninterior of said pressure-containing section and interior of saidtubular liner; and (c) a fluid inlet port defined in saidpressure-containing section and communicating with said interior of saidpressure-containing section, and wherein a near-end portion of saidtubular liner, attached to said outfeed end of said tubular body in aright-side-out configuration, with an integrally attached uninstalledportion of said tubular liner extending through said mouth and throatand thence through said interior of said pressure-containing section tosaid near-end portion in an inside-out configuration, whereby anincreased fluid pressure within said pressure containing portion canurge said tubular liner to extend itself within and along said pipe andinvert itself therein.
 31. Apparatus for use in installing an elongateflexible tubular liner into a pipe, comprising: (a) a feeder supportapparatus; (b) a feeder having a generally tubular body constructed offlexible sheet material and including a mounting connector attached toand supported by said feeder support apparatus, said feeder having anopen mouth large enough to receive and permit longitudinal passage ofsaid flexible tubular liner in a flattened inside-out configuration intosaid feeder and through said mouth; (c) a throat spaced inwardly apartfrom said mouth along said feeder body; (d) an outfeed end adapted forfluid-tight connection to an inverted right-side-out near-end portion ofsaid flexible tubular liner so as to retain fluid pressure within aspace within said feeder and surrounding said inside-out portion of saidtubular liner between said throat and said outfeed end; and (e) a throatregulating mechanism engaging said throat externally of said body andpressing a portion of said throat inwardly around said inside-out partof said flexible tubular liner between said mouth and said outfeed end.32. A method of installing a flexible tubular liner in a pipe,comprising: (a) supporting a flexible, generally tubular feeder outsidea near end of a pipe in which a liner is to be installed by inversioninto said near end, with an inside-out portion of said tubular linerextending from a supply length of said flexible tubular liner throughsaid feeder to a right-side-out portion of said tubular liner integrallyconnected with said inside-out portion and attached to an outfeed end ofsaid feeder; (b) supporting and shaping a throat portion of saidflexible tubular feeder so as to limit passage of a fluid through saidthroat while forcing a quantity of fluid under pressure into saidflexible tubular feeder between said throat portion and said outfeed endof said feeder, thereby increasing fluid pressure within saidright-side-out portion of said liner and a portion of said feederadjacent said outfeed end; (c) feeding said supply length of inside-outtubular liner into said feeder through said throat, thereby causing aportion of said inside-out portion of said liner to invert itself intoan interior of said pipe; and (d) continuing to force additionalquantities of said fluid into said flexible feeder and thereby causingsaid supply length of said tubular liner to be everted into said tubularvessel.